Elastic-fluid turbine.



C. R. WALLER.

,ELAsfrIo FLUID Tummm. l APPLICATION FILED JUNE 10, 1909 1,096,081..Patented May 12. 1914 9 SHEETS-SHEET l.

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CML www C, R. WALLBR. ELASTIG FLUID IUBBINE. APPL'IO'ATION I'ILBD' JUNE1o, 1909.

1,096,081 Patented may 12, 19121,

9 SHEEThS-SHEET 2.,

"//wy I .3515A @Hom/up I WM f bmw Mfw C. R. WALLER.

ELASTIO FLUID TUBBINE.' .v :ArPLIoATIoN gILnD JUNE 1o, 1909. 1,096,081vme11te 1 May12,1914

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G'. R. WA'LLBR. BLASTIC FLUID TUBBINE.

APPLIOTIONTILED JUNE 10. 1909.

1:- 1 Patented May 12,- 19114w 9 SHEETS-SHEET 5.

vC. R. WALLER. ELASTIG FLUID TURBINE.

APPLIoA'TIoN FILED nm: 1o. 190s.

PatenteiMay 12,1914.

9 SHEETS-SHEET 0.

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G. R. WALLER. BLASTIG FLUID TURBINB. APrLIcATIoN rum) JUNI: 19. 1909.

(LR. WALLBR. ELASTIG FLUID TUBBINE. A PPLIoATIoN FILED JUNI: 1o, 1909.

1,096,981. PatentedMay 12,1914.

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I l y im G. R. WALLER. ELASTIG FLID TUBBINE. APPLICATION FILED JUNE 10,1909.

Patented May 12,1914.

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' CARL RICHARD 'WALLE-n, or Tn-ENTON, NEW-JERSEY, AssIGNoR To DELAVAL-STEAM.

TURBINE COMPANY, 0F YORK, N..Y., A CORPURATON 0F NEW JERSEY.

`Appliteatioli ledune'lO, 1909. "Serial No.501,29 7.

nnn, a subject 'of the King of Sweden, and-aresident of T renton,'countyof Mercer, and

State ofNew Jersey, have invented certain new and useful Improvements 1nElasticlFluid Turbines, of which theollowing is a specification.`

This invention relates to improvements in elastic iiuid turbines,andfpartlcularly to im'- provements in turbines designed to be operatedinterchangeably or simultaneously upon steam of a plurality ofdifferent' pressures, derived. from a corresponding plurality ofsources.l An example of'such turbines is, a turbine 4designed to beoperated interchangeably or simultaneously upon high pressure steamderived from al boiler or other` suitable source, and upon. exhauststeam derived from some other engine.

It is highly-desirable, in .the case-of exi haust turbines, that asgreat a proportion of the load on the turbine shall be carried by meansof the exhaust steam as possible,

the high pressure or boiler steam being used only to supplement theaction of the exhaust` steam. Since the load on the turbine may be`variable, and since the supplyA of exhaust s team to the turbine may bevariable, I havel foundV that it is desirable to provide automaticgoverning meanswhi'chshall admit' to the turbine only that amount ofboiler or high pressure steam requiredtosupplement the action of the lowpressure o1 exhaust steam; and in the governing mechanismhereindesc'ribed, two valves -are provided, one controlling the supplyof exhaust or low pressure steam, the other controlling the supply ofboiler or high pressure steam, these valves lbeing operated by suitablemechanism so that, in regulatingthe supply of steam to the turbine, thehigh pressure valve remains closed altogether until the low pressuresteam proves insufficient to enable the turbine' to carry its load, andthen such high pressure valveis opened to such extent ,only Vas isrequired to enable the turbine to carry its load; such mechanism beingfurther so arranged that, upon decrease 'of load 'of the turbine, thehigh pressurevalve regulates the supply of high pressure steam to theturbine, the low pressure valve remaining wide open, until high pressuresteam is no longer required. and then said high prossur'e valve isclosed entirely, and further reg,-

nLAs'rIc-FLUID T-URBINE;

u lation ofthe action of. the turbine is e'ected, for lower loads byadjustment of the low 'pressure valve. In this way all of l.the lowpressure steam available is utilized, and only" so much-high pressuresteam is employed as s required to enable the turbine to carry its oa lIn the specific embodiment of my invention herein illustrated anddescribed, I have shown a' turbine of well known type, coinprislng asingle rotary blade-carrying member, and a plurality. of nozzlesarranged tol project steam against the blades of said rotary member,certainof these nozzles being "understood to be -ofa shape adapting themfor eiiicient use of l'ow pressure steam, and other of sa1d nozzlesbeing understood to be of a shape adapting them for eiiicient useillustrated separate valves for regulating the supply of steamseparately'to .these two' 'classes ofnozzles, and two independentcentrifugal governors, one adjusting th'ehigh pressure valve, the otheradjusting the low pressure valve. In a companion application of evendateherewith, docket No. 3516, I illustrate and describe other turbineregulating means embodying the broad invention likewise embodied in theturbine herein illustrated and described, but specifically different in,among other features, thatv a single governor controls both the highpres-l sure'valve and the low pressure valve inthe manner hereinbeforedescribed. t

My invention consists in a turbine'having means controllinglindependently the supply ,of steam orother working fluid of two or morediiierent pressures, such means arranged to carryv as great a proportionof the load of the turbine by the'action of steam of one such pressureaspossible; and my' invention further-comprises other features hereinafterdescribed and particularlypointed out in the' claims. l

The objects of my invention are to improve turbines intended to beoperated si multaneously upon working. fluid derived atdifferentVpressures-from a plurality of sources; to operate successivelyajplurality of valves controlling supply of working fluid -from aplurality of different sources; to carry as great a proportion 'of theload 'as' possible by'` working fluidof one. pressure, admitting onlysuchl proportion of working fluid of the'other pressure or pressures asof high pressure steam; and I have further .Specification of LettersPatent. Patented fayglg" 1914;.

25 .partialsction of the high pressure. governs' mayV be required tovcarryg'tlle loadgfand to l 'make the turbine relatively simple, compact,

eliicient and reliable.

'tion with 4re drawings.

` I will-'now' roeeedito" describe inven-v erencelto' the. .accompanyingInl'sfaid drawings; Figure 1 shows .an end A elevation of oneconstructioa'if 'of turbine V'embodyingmy invention, the gearing of tie`type of the turbine illustrated, and. the' cen, t'rifug'algovernorsthemselves," being omit-.

'i I ted. Fig. ,2 shows a. central horizontal sectionthrough the saidturbine, the same parts being omitted as are omitted in Fig-.1. Fig. 3Shows fa central vertical section oft-hepartsillustrated in Figs. 1 and2'.'4 .Fi'g.,4

. shbws'a vertical section of the turbine taken on the line of Figs.2.a1nd'3, looking in the direction of the arrowg this 'section beingtaken through the steam/chest ofthe turbine.l Fig. 'shows a.detail-*front eleva- -tion and partial section of the nozzlering ofthe"'t11rbine and.' Fig. 6 shows a detail `-transverse fragmentary{sect-ion of'said noz'- zle ring.A Fig. 7 showslan end 'elevation'anding valve' mechanismgand associated parts',

'and Fig.' 8 shows acentral' vertical section of said parts, the sectionbeing taken on the line y-'y of Fig. 7, looking' inthe' direction ofthe'arrows. Fig. 9 shows a detail'verti-l cal section of the lowpressure governing .valve and an elevation-and partial section ofassociated parts, 'including thel centrifugal governor for' adjustingsaidyalve, andv Fig. 1`0 showsl a detail longitudinal sect-ion of saidgovernor, on a larger scale. Fig. 11

- is a detail elevation and partial sectionillustrating an alternativeform' o f low pressure' governing valve; and Fig. 12 is a detail side'elevation of such parts.- Fig.` 1 3 a top 'viewv of the turbine,- thecover of its gear case having'been removed. A

In the drait'ings,` 1 l'designates the v casing Y of-Lthe wheel chamber.of the turbine, 2 desf ignates the rotaryl bucket-carrying wheel withinsaidA casing,v and 3 designates the shaft f upon which said wheel ismou'nted. 4,4 desv lignate the buckets ofsai-d wheel.

5' designa-tesa nozzle ring such as employed in this class of turbines,and 6 designates a low pressure primary steam chest constituting anannular l'chamber wit-hin casing 1. Thenozzle ring 5 separates this lowpressure steamzchest-G from the wheel chamber 7, saidnozzle ringcomprisinganl annular portionl 8 projecting through a correspondingannularspace formed in the cas-v l ing 1 and in -lthisannular portion 8ofthe nozzle-.ring there isa secondary steam chest- A9. For conveniencein -fgovernin' this .sec- Aondary steam chest is customarily dividedinto a plurality of-separate chambers 9,.9,

corresponding vvalve '11i the `s telllsfl .Pf these.valves, in theconstruction shown in lthe drawings, extending outward through .Suitablestuflingboxes 13"and being pressure steaml toithe' low pressure steamtimetc., and in the wall 'of the annular portion I8 of thc-nozzle ringopposite certain ofthe chambers', 9", etc., are a plurality ofvalveseated 4openings' 10, one for each such chamber;v and for. eachs'uch'opening there isy a arrangedto be operated by suitable'hand le-Yvers 14; As'many expansion nozzles. 15' may lead-from onefogf these'chambers 9, 9?, etc., yas 'found convenient; In the constructionshown,'two' nozzles 'lead rome'ach. such chamber, but -this 4l'minbe'risnot material and will loe-varied as ,makes'desirable v convenience lofdesign is' provided 4 with'l an admission port 16,' to

. 80 The low pressureprimarysteam chest 6,

which steam is conducted by'conduit 17 having in ita suitableregulatingvalve 18. The

valve 'openings 10 serve to 'lead the low steam chest6, to thecorresponding nozzles g5 pressure. or exhausts'team from'jthe primaryIv15. High` pressure steam is conveyed to i other nozzles 15 by pipes 19`passing through suitable stutli'n'g boxes '19"L inthe front of thecasing 1, andscrewed into correspondin chambers 9W, 9*, etc. These pipes`19 lea from aghigli--pressu'resteamgchest- 20 (Figs.

provided for regulating 'independently -the 7 and 8) in ,which Vsuitablevalves 21 are .9'.5-

supply ofhigh-pressure steam to the several f pipes 19.` High' pressuresteam is supplied to this 'steam chest 20 through a port 22 and.

balanced valves'- 423 controlling -passage through, valve openings 24;?"These balanced ,yalves v23' are operated by one". of 'the gov-l ernorshereinbe ore mentioned and herein? loo after-described. In connectionwith' this 1" high ypressure steamchest 2021 have provided an emergencyvalve 25 and meansxcon-f' Ordinarily itis no tdesirableto supply highIon the turbine, thenheemergency valve 25' 'admitted tothe l'ow pressuresteam chest 6 may be opened` and` high Ipressure. steaminsuieient'lquantity-,to carry the loadf The low' pressure' governingvalvef- 18,y .shown particularly in'Fi'gs. LLand 9, is also' a balancedpuppet valve, comprising two .valves 25 mounted upon ,the same stem 26.

and controlling' valve openings 27; This ed to a vbell crank lever 2 9arranged to lbe ac.

trolled thereby vfor conveying-high` pressure i l steam to' the low'pressure steam `chest 6.

:valve stemj extends downward through a .suitable .stuffing box28'and-is there' connectno gaged by ano-ther 'speed governor 36. Aniother arm of' this lever 34 is engaged by agovernor spring 37, tendingto hold valves 2o open.

I do not limit myself to any particular type of speed governor foradjusting the high pressure and low-pressure valves, but the particulargovernor "illustrated .in Figs.v

venient for the purpose, and comprises cen,- trifugall Weights 3S havingknife redges 39 'bearing against a disA 40 mounted on a shaft 4l,andsprings 42 and 43 pressing against a.

vdish itself pressing against the heads of screws 45 carried by theinner end of the governor Weights 38. It will be obvious that asshafti-l rotates, these governor Weights 38 tend` to iiy out, suchtendency re sisted by the springs 42 and 43, and also by the spring 3lshoivn in Fig'. 9, and 37 in Fig.

8; such movement of the governor-Weights, being transmitted, throughdisk 44, to'a stem 45. The stem 45 ot the low pressureV governorbearsagainst the adjusting ,screws -46 carried by the bell crank 29; andthe similar stem 45 of the highpressure governor bears against theadjusting screw of arm 34. As already explained, the springs of thesegovernors are so adjusted, that, during increase in load, the highpressurevalve 4remains closed until the 10W pressure valve is' 'wideopen; after Whichif the load so requires, the high pressure valve opens;and upon decrease in load, the high pressure valveis closed entirely 'byits governor' before the low pressure valve beginslto close at all. v 'lAs shown particularly in Fig. 13, this turl bine comprises, as is usualin turbinesof the particular type illustrated,4` pinions 47 mounted uponthe turbine Wheel sha-ft 3 and interineshing with gears 48 on oppositesides ot' the pinions 47, and themselves mounted upon two shafts 4l.Froml either of these shatts 4l power may be taken cti. On these shafts4l the speed governo-rs 30 and 36 mentioned, aremounted. The fact thatthe type of turbine illustrated has two shafts rotating at relativelylow speedand from which poiver'is, or may be, taken oil',-

inakes it very convenient to operate two governors separately, one forcontrol of high pressure steam, and the other tor control of e5 lowpressure steam.

In the operationof this turbine, as -al-y ready described, the governorsso operate that as great a portion of the total powerldeveloped aspossible, is developedfrom 'the low pressure steam; such regulationbeing automatic. But the operator may, and will customarily,- controltheoperation of the turbine more or less, by hand, by cutting various.of the' high pressure and low pressure nozzles into and out of action,means of the valves 2l and'll, respectively', so that, if the loadcarried is materially less than the loW pressure steam alone is able'tocarry, only apart of the low pressure nozzles. will be in service; or'if the load carried is such as an to require some, hut not all ofthe'high pressure nozzles, some ot thesehigh pressure nozzles will beout of service; the purpose being lto avoid throttli'ng and Wire-drawingas much as possible, by having only those nozzles inservice which are4absolutely re- .quired for carrying the load; the low pressureregulating valve being therefore, cus, tomar-ily, Wide open, and .thehigh pressure regulatingl valve on the point of opening; though wherethe load conditions, vor the supply of high pressure and low pressure .steaui, are very variable, a greater Working margin may be provided byleaving open morenozzles than are absolutely'-required 95 vby conditionsexisting at the moine'nt.-v As previously explained, when the supply ofloivpressure steam proves to vbe inadequate, or when there is partialfailure in vacuum conditions, impairing lthe etfective ness of the lowpressure nozzles, the emergency valve lvmay be opened,-perniittiv` f a.portion of the high pressure steam` to now into the low pressure steam'Achest 6, and thenceto the low-pressure nozzles; but in such case,'thevalve 25 will customarily be open onlyto such extent thagdue tothrottling atv this valve, the pressure in the low pressure-steam chestwill be little, it any, higher than ordinarily the case, so that theilolw"A pressure nozzle may, even at such times, Work With besteiiiciency; But if excessive overloadiis to be carried, so that ycatedfor this ur ose a butt'ertl valve 49 125 in the low pressure supplypipe, the stein of which valve extends through to the outside andlcarries a bell crank lever 50, vto one arm of Which a spring 5l isconnected, While the other arm is connected by a link 52 to a 13opivotedA arm 53 carrying at its lower .end an I adjusting screw '54arrangedv to be acl-,uated by a4 governor .30.

'Ity willbc a parent that the turbinepmay'- be started eit er withlow'pressure steamv or with high pressure steam, as. may be mostconvenientyand. that afterthe machineis in operation, the governors will.automatically adjust the valves so that as great a pro-' portion` aslpossible of the load will. be -carj ried by'thelow pressure steam.`

iftl will of course pe apparent that, shouldn `there, bev any occasionfor doing so, the gov- "ernor 'can be so'l adjusted that as much aspossible of the load is Carried by the high pressure steam, andthe lowpressure steam is used onlytosupplement the action of the high pressuresteam. 'It will also be .understood-t-hat', in the case 'ofa turbine ofroper capacity with respect to the load to e carried,fthe ,tnrbine'cancarry its full loadA at normall speed if operated either with low'pressure steam alone, or ywith high pressure steam alone, or ifoperated partlyl with high pressureand partly with lowpressure stem.What I claim is 1. An=elasticfluid turbine comprising in combination arotor, high-pressure-working- -fluid's'upply means andlower-pressure-working-'fluid'supply/m'eans therefor, and independentcentrifugal governors for such high pressure working fluid .and lowerpressure 'working fluid respectively, the high pres-v sure governorarranged topermit supply of high pressurefluid only after the supply oflow pressure fluid is begun.

2.' An elastic fluid turbine comprising in combination a rotor,high#pressure-workingf nors,fone controlling `the. supply of 'highsfluid and lewpressureeworking-fluid supply means therefor, valve meanscontrolling the;

supply of high pressure .and low pressure working fluid, and twocentrifugal gever,-y

` pressure fluid and the other controlling the supply of low pressure`fluid, saidY governors arranged to act one in advance of the other.

3. An elastic fluid turbinecomprising in combination a rotor,high-pressure-workingfluid and low-pressure-working-fluid supply meanstherefor, valve means controlling the supply of high pressure and lowpressure. workingfluid,-and two centrifugal governors, one controllingthe supply of high pressure Vluid and the other controlling theV supplyof low pressure fluid, said high pressure governor arranged to admithigh pres 'sure fluid only when the supply of low pres`` p sure fluid issubstantially unrestricted.

.Giol

564, An elastic fluid turbine comprising in combination a rotor,high-pressure-workingfluid land low-pressureworking-flud supply meanstherefor, valve means controlling the nors, one controlling thc supplyofhigh presl upply ofd high pressure and low pressure working fluid, `andtwo centrifugal gover-l 65 rocciosi sure fluid, and the, other controllio thesupll ply of low pressure fluid, said hifg pressure governorarranged to admit high pressure` .working fluid after the admission oflow l pressure working Yfluid' is begunffand to shut 'off supply" ofhigh pressure working, fluid befo're supply of low pressure workingifluid l 5.- An .elastic uuid 'turbine comprising in" combinatmn arotor, -hig'h ressureand low pressure nozzles for supplying workingfluid thereto, high pressure valve means, low pre`s.

sure valve means, and independent'centrif"` f ugal governors, for 'thehighl pressure and low pressurevalve means, respectively, arranged tobegin the supply of-highpressure fluidafter the supply of low isbegunand todiscontinue 1e Vsupp of high pressure fluid before vthesupply ofylowV vpressure fluid isdiscontinued.Vv

pressure fluid t v @Alll elastid fluid turbine ,comprising a high speedrotor, lower speed shafts driven thereby, high pressure working fluidand low pressure working fluid supply means,

.arid two governors, driven by said lower speed shafts, one suchgovernor controllin `and the other controlling the supply of lowerpressure Working fluid,"said higher pressure supply means arranged tobegin supplyof.

high pressure fluid after'the supply of -lowf 'pressure fluid is begunandv to .discontinue,., A'the supply'of high pressure fluid before thesupply of lower pressure working "fluid is dis'- continued.

d. An elastic fluid vturbine comprising a' vprimary steam chest, aplurality of second' los ary steam chests, lcertain of 'said .secondarysteam chests 1n. communication with said l primary steam chest, andothers of such secondary steam chests notvin communication wlth saidpr1mary steam chest, working -liuid-supply-means for the primaryl steamindependent working-fluid-supply-- chest,

means for the secondary steam chests which are not connecte-.d to 'saidprimary steam chest, nozzles leadingl from the secondary steam chests,and a. rotor against .which said `nozzles are arranged to projectexpanded working fluid, the nozzles of the twov groups of secondarysteam` chests being of different expansion ratio but adapted to expandto the same terminal pressure.

9. An elastic i fluidturbine comprising a primary steam chest, a.plurality ofsecondary steam chests, certain oflsaidtsecondary other, andto close it before the other.

10. An elastic fi'uid turbine comprising a primary steam chest, aplurality lof secondary steam chests, certain of said'secondary steamchests in communication with Said .primary steam chest and others ofsuch secondary steam chests not in communication withl saidprimarysteamV chest, Workingfluid-supply-means for the primary. steamchest, independent nv'orking-iiuid-siipplynie-ans for the secondarysteam chests which are not connected to said primaryl steam chest,nozzles leadinglfrom the secondary steam chests, and two independentgovernors, one for each of said supply means.

11. An elastic fluid turbine' comprising a primary steam chest havingWorking-Huidsupply-means, a plurality of second-ary steam chests,certain of said secondary steam chests in communication yvi-th saidprimary steam chest, independent working-fluid-supply means for otherof'such secondary steam chests, nozzles leading from such secondarysteam chests, valve-means controlling passage' (if-Working fluid fromsaid primary= steam chest tothose secondary steam chestsfv which areconnected to said primary steam chest, and governing meins controllingseparately the supply of steam to the primary steam chest and to thosesecondary steam chests which are not connected to the primarysteamchest.

lf2. An elastic fluid turbine `comprising a turbine casing having in ita rotor chamber, a primarI steam chest and a plurality of secondary.ffeam chests, said secondary steam fhests }".;:ovided with means fordischarging `Working fluid into said rotor chamber, valves connectingcertain of said sec-` ondary steam chests with said primary 'steamchest, a further steam chest and means connecting the rsaine with,others. of said secondary steam chests, and governing means controllingthe supply of Working fluid to said primary steam chest and to saidfurther steamchest. l l 1 il* 13. An elastic fluid turbine comprising i'turbine casing having in it a rotor chambe secondary' steam chests, saidsecond ary steam chests provided with means for discharging Workingfiuid into said rotor chamber, valves connecting certain of saidsecondary steam chests with said primary steam chest,

a further .steam chest,- -a,iitluits connecting the same to others ofsaid secondary steamchests, and passing through said primary steamchest, such 4conduit having independent controlling valves, andgoverning means contro-lling the supply of Working fluid to said primarysteam chest and to said further .steam chest, i

1st. An elastic iuidturbinecomprising'a turbine casing'having init arotor chamber,

a primary steam chestand a plurality of secondary steam chests, sald'seco-ndary steam chests provided with means for disl charging Workingfluid into said rot-or cham-- ber, valves connecting certain ofv saidsec-l ondary steam chests With said primar f steam chest, a furthersteam chest, conduits connecting the saine to' others of sald secondarysteam chests, and passing throughV ber and arranged all to directWorking fluid' directly against theLsame series of buckets, the nozzlesof certain of said steam chests of -difterent expansion ratio than thenozzles of others of said steam chests, independent;=Working-f1uid-supply-means for the steam' :chests hav-ing expansionnozzles of different' ratios, and independent governing means for saidindependent Working fluid supply means, arranged to supply working fluidtoy the expansion nozzles of one' 'atio of expansion after Workingfluidhas been supplied to the nozzles of another ratio of expansion.

v1G. An elastic Huid turbine comprising a turbine casing having in it arotor chamber, a rotor therein having a series of buckets, a

plurality of separate steam chests in said casing and expansion nozzlesextending from said steam chests to the rot-or chamber and arranged allto direct working fluid directly the others of said steam chests,independent ,g .Working-flugl-supply-means for the steam a primary steamchest and a pluralityof chests having expansion nozzle'so differentratios, andi-ndependent centrifugal gever-- ferent expansion ratio thanthe nozzles of' nors for said independent Worling-iuidsupply-means,arranged to supply Working fluid to the expansion nozzles of-one ratioof expansion after working Huid has beenV expansion.

supplied to' the nozzles of another ratiol of 17. elastic fluid turbinecomprising a turbine casing having V1within1 ita primary steam chestvand a lrotor chamber', `and a nozzle ring within said casing havingwithin it a plurality of secondary'steam-chests, certain 'of which arein .communication with saidnprimaryI steam chest, independent vsupplymeans for conveying Working fluid to the other secondary steam chest,andexpansion' nozzles extending from said secondary steam chests. c

18. An elastic fluid turbine comprising aturbine casing havingnwithin ita primary stean'ichest and a rotor chamber, a nozzle ring ',Within saidcasing 4and betweenfsaid primary steam chest and rotor cliambeiflfiavingwithin it a plurality of Secondary steam chests, certain of which are incommunication With said primary steam chest, supply conduits extendingthrough the primary steam chest to others of said secondary steamchests, and expansion nozzles leading from said secondary steam cheststo the rotor chamber.

Sure turbine., `0f., Acontrol-,ling the admission ot low pressure 19. Anelasticifluid turbine comprising a turbine caslghavingrwithin it aprimary vst ea1rn-chest and arotor chamber, a nozzle vvithin saidcasingand between said primarysteam chest and `rotor chamber, having Within it-a .plurality o f secondary steam chests, valve-seated openingsconnecting certain of said secondary steam chests with said primarysteam chest, valves operable from the exterior of the turbine casing,`for said openings, independent supply means for others 'of saidsecondary steamchests, and

expansion nozzlesleading from said secondary steam chests to the rotorchamber.'

20. The combination with a mixed presn,"speed governors, 'one

